538
ACUS03 KWNS 210733
SWODY3
SPC AC 210732

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0232 AM CDT Tue May 21 2024

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
OKLAHOMA AND KANSAS INTO THE ARKLATEX VICINITY...

...SUMMARY...
Severe thunderstorms are possible across portions Kansas and
Oklahoma into the Arklatex region on Thursday. Damaging gusts, hail
and a couple of tornadoes will be possible. Isolated strong to
severe thunderstorms also will be possible across the central Plains
into South Dakota, and across the Mid-Atlantic and Northeast coastal
areas.

...Mid-Atlantic and Northeast...

Broad, low-amplitude southwesterly flow will persist across much of
the eastern CONUS on Thursday. Some enhancement of mid/upper flow is
forecast across from the Northeast states as a compact upper
shortwave trough glances the international border. At the surface, a
cold front will move east across the Northeast. This will focus
thunderstorm activity during the afternoon from VA northeast along
the Atlantic coastal vicinity amid a seasonally moist airmass.

Modest destabilization and steepening low-level lapse rates are
forecast. Strong gusts will be possible with thunderstorms during
the late morning into the afternoon. A plume of modest midlevel
lapse rate also will overspread the region, and vertical shear will
be sufficient, especially from NJ northward, to support sporadic
marginal hail as well.

...Plains Vicinity...

A subtle upper shortwave trough is forecast to migrate across the
southern Plains and Mid-South vicinity, while another deepening
shortwave trough overspreads the northern/central Plains. Both of
these features will result in increasing mid/upper southwesterly
flow (30-50 kt) on Thursday.

At the surface, lee cyclogenesis is forecast over the central High
Plains. A surface low will progress east across SD/NE to IA/MN, with
a cold front developing east/southeast across the northern/central
Plains during the evening/overnight. Meanwhile, a dryline will
extend southward from a secondary low over western KS into central
TX. Strengthening low-level southerly flow in response to the
deepening low will transport Gulf moisture northward ahead of the
front, with near-60 F dewpoints as far north as NE. Richer
boundary-layer moisture (mid 60s to low 70s F) will remain farther
south.

Strong destabilization ahead of the dryline and increasing
large-scale ascent will support thunderstorm development during the
afternoon across the southern Plains vicinity. One or more clusters
will track southeast through the evening into the ArkLaTex region.
All severe hazards appear possible. Severe potential may be less
with northward extent into NE/SD and vicinity given more modest
moisture, but at least isolated strong/severe storms appear possible
given an otherwise favorable environment.

..Leitman.. 05/21/2024

$$